Carbon scraper



Dec. 15, 1931.

WQ- a? c. C.H LAWSON 1,836,415

CARBON SCRAPER Filed March; 16, 1931 Patented Dec. 15, 1931 'uuirau stares mortar err-ice La i wii (2? ea on i: QBJ Dense, IQWA Application m a March 16, 1931. Serial No. 523,138.

' of different diameters and having groovesot different widths.

More specifically, an object of: the. invention is to provide,animprovedacarbon scraper including a pair. t spaced annulanpl-ates designedto embrace a, piston, a plurality'of bit bars being slidably mounted between; the; plates and being capable of: projection toth desired extent'into the space defined by the central opening. of; said: plates. for. engaging piston ring grooves, whereupon the entire tool may be manually oscillated for causing the bit barsto scrape and removecarbon deposits;

'Another object of the invention ist-o pro.-. vide a universal carbon scraper which is,

simple, durable and comparatively inexpensive; 1

With these and other objects in view, my invention consists in the. construction, ar-

rangement and combination of. the. various. partsof my carbon scraper, whereby the objects contemplatedv are attained, as hereinafter more fully set forth, pointedzout in my claims, and illustrated-in the accompanying drawings, in which Figure 1 is a plan View of a tool embodying my invention, the full lines showing the toolin its normal position of parts and tlie dott ed lines indicating a position which; may be assumed by the parts for operation of the device. I

Figure 2 is a plan view showing the base plate and bit bars of the tool in position for practical use relative to a piston, the top plate of the tool beingremoved'for the purpose oi? better illustrating the parts.

Figure 3 is a detail section on theline 3?3 of Figure 1, illustrating particularly one of li the slidable bit bars and its slide bearing. I

gu e l s. a e aildge e evation at the parts shown in Figure 3 F gu e ,.i p n view of a egme tal por onc t he tool, t i lust ate part cularly the posi on assume by o e. at the par s n 55 he ope t n at separa i g he twoannular.

plates after thebit bars have beenremoved;

Figure 6is asectionalielvation onitheline 6.6 of Figure 1, illustratingthe ha dlesot. the tool. in compressed relation.

. a 60 I. employ a pair Qis nnlar annular-plates which for. convenience I have designated as, a base plate 10., and; a, top. plate .2, altho gh it is to be understoodthat the toolmay. be used; equally as well in the inverted position asin the position illustrated.

Fixed toeachuoii the plates 10 and: 1-2 is av substantially radially projecting handle, these handles being designated respectively by the numerals 14 and 16. The handles Lt and 1,6, are adapted tobe grasped Conjunctively in one hand of, the operator for oscillating the tool in use and alsoior causing an adjustment of the relative positions. of the top, plates for purposeswhichwill be madeclean.

The handles 1 L and 1s6 preferably are made, I

of, channeled bar-s havin their open sides opposedtoeach otherand serving toreceive, the end portions of an expansion spring 18. It isthe function ofxthe spring 18 to tend to move the handles 14 and: 16 awayfromeach other and yieldingly hold the par sv ofthe, tool in expanded position, as illustrated by, the full lines in Figure 1'. i

A plurality of radialpockets or slide bear;- ings 20, in this instance, three in number, are mounted on'the inner face of the base plate 1,0. each of the slide bearings 20 is slidably mounted for reciprocation a bit bar 22. Each bit. bar 22has on its upper surface a pin 24;, which projects through a longitudinal slot 26, in, the top Wall of-its slide bearing. The slots 26 extend to the outer ends ot-the. slide bearings, so that the bit bars may, be, em ved ttime by ou wa lw Q I ll- Each bit bar QQcarries atone end a cutting b t nd at he ot e end, a. t ng ase he cut ns its 28' an 1P e tab a are formed y produ ng a V-shaped' n tch n. he e d. f th b w by two V rtical y extending teeth are produced at the end of the bit. The cutting bit 80 eXtends across the entire vertical thickness of the bit bar 22, whereas the cutting bit 28 is of less depth and is capable of being used in a piston ring groove of less width than the bit 30.

The annular plates 10 and 12 are assembled with the spring 18 between the handles 14 and 16 and with the bit bars'22 in the slide bearings 20.

The bit bars 22 may be arranged selectively so that all of them present either the narrower cutting bits 28 at the inner periphery of the annular plates or with all of the wider cutting bits 30 in such position.

The handle 14 is formed with a lug 32 which overlies the outer marginal portion of the top plate 12 and the handle 16is formed with a similar lug 34 which overlies the outer marginal portion of the base plate 10. The lugs 32 and 34 serve to assist in preventing accidental separation of the plates.

The slide bearings 20 are formed at their inner ends with lugs 36 which project around and slidably engage the inner periphery of the top plate 10. These lugs also serve to assist in preventing accidental separation of the plates and to guide them in their movements of relative rotary adjustment.

The pins 24 of the bit bars 22 are of sulii' cient length to project slightly through slots 38 formed in the top plate 12. The slots 38 extend substantially across the plate 12 and are formed on lines inclined relative to radial lines.

In the normal position of the parts the expansion spring 18, by engagement with the handles 14 and 16 fixed to the respective plates 10 and 12, causes the bit bars 22 to be withdrawn outwardly to their fullest extent so that their inner ends are substantially concealed between the plates 10 and 12 and the pins 24 engage the outer ends of the slots 38.

lVhen it is desired to use the tool, the handles 14 and 16 are grasped in the hand and the annular plates are caused to embrace and encompass a piston such as 40 as indicated in Figure 2. The tool is moved lengthwise of the piston until the bit bars 22 reach the plane of one of the piston ring grooves such as 42. Thereupon pressure is applied to the handles 14 and 16 to compress the spring 18 and cause limited relative rotary movement of the plates 10 and 12 to the position inclicated by'dotted lines in Figure 1. This movement, because of the engagement of the pins 24 in the inclined slots 38, causes the bit bars 22 to be projected inwardly toward the piston 40 and to enter the grooves 42. Then the entire tool is caused to oscillate about the piston and the selected cutting bits of the bit bars serve to scrape and remove accumula tions of carbon within the groove.

When pressure is removed-from the handles 14 and 16, the spring 18 moves them apart and causes the bit bars to be withdrawn so that the tool may be removed from the piston or may be moved to new location for cleaning another groove.

Preferably the outer end portions of the slots 38 are curved or inclined relative to the main portions of said slots, as shown in Figures 1 and 5, and designated by the numeral 38. This arrangement is for the purpose of facilitating the initial movement of the pins 24 in the slots because of the fact that initial pressure on the handles causes a lateral thrust of the pins against the walls of the slots. After the movement is started the pins travel readily in the slots and the inward limit of movement is defined by engagement of the pins with the inner ends of the slots or by mutual contact of the adjacent margins of the handles, or both. It will be understood that the bit bars 22 1 are removable from their slide bearings for the purpose of making a selection as to which of the bits 28 or 30 will be used in a given operation.

To effect the removal of the bit bars from their bearings, the outer marginal portion of the top plate 12 is manually sprung away from the base. plate adjacent the location of one of the slide bearings, as indicated by dotted lines in Figure 3. The pins 24 project only a slight distance beyond the surface of the top plate and this springing movement is sufiicient to disengage the pin from the slot and thus permit the bit bar to be Withdrawn outwardly by manual movement, the pin passing out through the open outer end of the slot 26 in its slide bearing. The bit bar may then be reversed and replaced in posi tion, and this operation is of course performedon all of the bit bars so that they will present corresponding cutting bits for use at the inner periphery of the plates.

At times it may be desirable to disassemble the parts of the tool and to separate and remove the plate 12 from the plate 10. In order to do this the bit bars 22 are first removed in the manner above described, thus permitting thespring 18 to move the handles 14 and 16 farther apart than could be accomplished when the bit bars are in place because such'movementis normally limited by engagement of the pins 24 with the outer ends of the slots 38.

This additional movement of the handles and consequently of the plates 10 and 12 is sufficient to bring the lugs 86 into registry with marginal notches 44 formed at the inner periphery of the top plate 12. This position of the parts is illustrated in Figure Then the plates 10 and 12 may be moved apart manually beginning at a point substantially opposite to the locationof the handles 14 and 16 and continuing until all of thelngs 36' have been withdrawn through the notches 44 rea ers and the lugs 32 and 34 and have become disengaged respectively from the outer margins of the plates 12 and 10. A reversal of these operations will result in re-assembling of the parts and when one of the bit bars has been placed in position the engagement of its pin with the end of a slot 38 will result in holding the parts in such position that the lugs 86 are not in alignment with the notches 44. In other words, the lugs 36 by engagement with the inner periphery of the plate 12 will hold this plate in its proper position relative to the base plate 10.

It will be observed that this tool may be used in connection with pistons of many diameters, ranging from the smallest diameter which could be engaged by the bit bars 22 in their innermost limits of projection, to one of the largest diameter capable of being received within the central opening of the an nular plates. It will also be observed that the tool may be used for piston ring grooves of difierent widths because the bit bars may be placed in either of the two selected positions for using either the thin bits 28 or the thick bits 30. This makes the tool substantially universal and capable of being used on practically any kind of engine piston.

The bit bars 22 preferably are made of rather soft brass in order that they may not in their operation tend to scratch or otherwise mar the metal surface of the ring grooves upon which they operate.

I claim as my invention 1. A carbon scraper comprising a pair of annular plates adapted to encircle a piston, a series of bit bars slidably carried in radial positions by one of said plates, a handle fixed to and pro ecting from the periphery of each plate, interengaging means: for holding the plates in spaced relation with the bit bars between them and for permitting relative rotary movement of the plates, said handles adapted to be grasped manually for oscillating the tool about a piston and also for compressing them to cause relative rotary movement of the plates in one direction, spring means tending to cause relative rotary movement of the plates in the opposite direction, and slidable connections between the bit bars and the other plate for projecting the bars inwardly toward the center of the plates when said handles are moved toward each other.

2. A carbon scraper comprising a pair of annular plates adapted to encircle a piston, a series of bit bars slidably carried in radial positions by one of saidplates, a handle fixed to and projecting from the periphery of each late, interengaging means for holding the p ates in spaced relation with the bit bars between them and for permitting relative rotary movement of the plates, said handles adapted to be grasped manually for oscillating the tool about a piston and also for comp ins hem to ca e at v tar y, more ment of the plates. in, one direction, spring meanstending to cause relative rotary move ment of; the plates in theoppositedirection,

andslidable connectionsbetweenthe bit bars and the other platefpr projecting. said; bars inwardly towardthefcenter of; th plates whenv said: handles are moved, toward each other, said bit bars havingcutting bits. of

difierent widths on. their respective ends and belng reversibly mountedwith respect to said plates.

Z"). A device of. the character set forth, com; prlsing, an annular plate formed with a se ries of slide bearings. radially arranged, a

rection, spring means for causing relative rotary movement of the plates in the other direction, and connections between the bit bars and said second plate whereby said bars are caused to slide in their bearings as one plate rotates relative to the other.

4. A device of the character set forth, comprising an annular plate formed with a series of slide bearings radially arranged, a

handle projecting from the periphery of said plate, a bit bar slidably mounted in each slide bearing, a second annular plate arranged parallel with the first and with said bit bars between them, a handle on the second plate adapted to coact with the first handle for conjunctive manual engagement for oscillating the tool, and also for causing limited relative rotary movement ofthe plates in the other direction, connections between the bit bars and said second plate whereby said bars are caused to slide in their bearings as one plate rotates relative to the other, and means for normally preventing separation of one plate from the other.

5. A device of the character set forth, comprising an annular plate formed with a series of slide bearing radially arranged, a handle projecting from the periphery of said plate, a bit bar slidably mounted in each slide bearing, a second annular plate arranged parallel with the first and with said bit bars between them, a handle on the second plate adapted to coact with the first handle for conjunctive manual engagement for oscillating the tool and also for causing limited relative rotary movement of the plates in one direction, said second plate being formed with a series of inclined slots, each bit bar being provided with a pin projecting within one of said slots, whereby said bars are caused to reciprocate in their bearings when the second plate is rotated relative to the first.

6. A device of the character set forth, comprising an annular plate formed with a se- 5 ries of slide bearings radially arranged, a handle projecting from the periphery of said plate, a bit bar slidably mounted in each'slide bearing, a second annular plate arranged parallel with the first and with said bit bars between them, a handle on the second plate adapted to eoact with the first handle for conjunctive manual engagement for oscillating the tool and also for causing limited relative rotary movement of the plates in the other direction, said second plate being formed with a series of inclined slots, each bit bar being provided with a pin projecting within one of said slots, whereby said bars are caused to reciprocate in their bearings when the second plate is rotated relative to the first, each bit bar being formed with cutting bits of different widths at its respective ends and be ing reversibly mounted in its bearing.

Des Moines, Iowa, March 7, 1931. CLARENCE C. LAWSON. 

